Crop yield is subject to many factors including crop genetics, environment (e.g., air, soil and/or water) and cultural conditions. These factors must be optimal in order to realize maximum yield potential for growing crop plants. Crop plants whose fruit is the harvested commodity seem to be especially sensitive to stress factors which limit yield. Less than ideal conditions or "stress" may lead to smaller fruit size, limited fruit formation and/or fruit abortion which results in a net loss of yield.
Plant growth regulators (PGR's) affect the physiology of plant growth and influence the natural rhythm of a plant. More specifically, plant growth regulators may, for example, reduce plant height, stimulate seed germination, induce flowering, darken leaf coloring, minimize lodging of cereals, slow grass growth on lawns, reduce boll rot and provide better boll retention in cotton.
Diflufenzopyr (DFFP), a semicarbazone PGR, has been found to enhance the marketable yield of fruiting crops by increasing the harvested size and/or number of fruits retained by the crop. DFFP may thus also reduce the dominance of older fruits over younger fruits ("primigen dominance") resulting in enhanced fruit set and yield.
The yield enhancements achieved by the present invention may usefully be employed with crops that are especially sensitive to stress factors (e.g., cotton, tomatoes or the like) or which poorly regulate fruit load due to determinant growth (e.g., some soybean varieties), or so-called "alternate year" fruit producers (e.g., apples, pears, peaches, apricots, pistachios and the like).
Broadly, therefore, the present invention is directed toward the fruit yield enhancement by applying a semicarbazone in a fruit yield enhancing effective amount to the locus of a fruit bearing plant. Most preferably, the semicarbazone treatment is practiced at the onset of reproductive growth--that is, at the onset of the flowering and/or fruit reproductive growth stage of the plant. Most preferably, the semicarbazone is diflufenzopyr. By using such an early treatment strategy, improvements in the plant's fruit yield are achieved.
These and other aspects and advantages of the present invention will become more clear after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.